Double native is nonsense.
What you want to do (as per post #1) is for a given desired HiDPI resolution X by Y, create an entry for X by Y and 2X by 2Y.
thanks, but isn't 2X by 2Y double the values for X and Y?
in my case, 2560x1440 -> 5120x2880
i noticed that for your 1600x900 you didn't create this exact one, but created 2 custom ones (1366x768 and 1440x810), lower than 1600x900, maintaining the aspect ratio, and then another two at twice the X & Y values. Does this mean i need to first create something slightly lower than 2560x1440 and then make a HiDPI version of it?
I assumed running HiDPI 2560x1440 would be possible by creating the 5120x2880..
Did more testing and created 2048x1152 HiDPI, as well as 4096x2304.
Now I can see and use 2048x1152 HiDPI but 1920x1080 HiDPI disappeared from RDM..still, 2048x1152 HiDPI is nice, might as well use this one.
LE: seems that when using 2048x1152 Hidpi, the max available resolution for games is 1920x1080...so i have to switch to 2560x1440 (HiDPI, but still looks the same to me as the non-HiDPI one) in order to have it also in games.